The present invention relates to a sewing unit for the production of a seam.
A sewing unit for producing a seam in a sewing-material part generally includes a sewing machine, a sewing-material holder, which is displaceable relative to the sewing machine, a setting drive for positioning the sewing-material holder in an open position in which the sewing-material part is not grasped and a clamping position in which the sewing-material part is grasped, and a feeding plate for feeding the sewing-material part into the sewing-material holder with the sewing-material part folded around the feeding plate. The feeding plate holding the sewing-material-part is movable in a feeding direction (or a Y-axis) into the sewing-material holder which is in its open position and, after transfer of the sewing-material part and closing of the sewing-material holder, the feeding plate can be moved out alone from the sewing-material holder.
From Federal Republic of Germany Patent 16 60 839 (corresponding to U.S. Pat. No. 3,522,783) a sewing system is known in which a sewing-material part is transferred by means of a plate from a presentation station to an intermediate station, clamped there, and then taken over by a sewing-material holder and moved through a sewing machine in order to produce a seam. In order to obtain precise fixing and alignment of the sewing-material part, a tram rail is arranged in front of the intermediate station, which rail, during the feeding of the sewing-material part, rubs against the latter and thereby smooths it.
This operation requires a considerable structural expense in order to provide the different parts involved. Furthermore, it is necessary for the process that specific operations take place one after the other, resulting in considerable machine cycle time.